Combined therapy for cystic fibrosis

ABSTRACT

There is disclosed a combination of inhibitors of Tissue Transglutaminase (TG2), inhibitors of reactive oxygen species (ROS) and CFTR channel activators (potentiators) for separate, sequential or simultaneous administration to CF patients carrying the ΔF508-CFTR mutation, and pharmaceutical compositions thereof.

This non-provisional patent application claims priority to and benefitof European Patent Application No. 12168409.6 filed on May 17, 2012 thecontent of which is incorporate by reference in its entirety.

The present invention relates to the treatment of Cystic Fibrosis (CF)in patients carrying the ΔF508-CFTR mutation. More specifically theinvention provides a combination of inhibitors of TissueTransglutaminase (TG2), inhibitors of reactive oxygen species (ROS) andCFTR channel activators (potentiators) for separate, sequential orsimultaneous administration to CF patients carrying the ΔF508-CFTRmutation. Another object of the invention is a pharmaceuticalcomposition containing the TG2 inhibitor, the ROS inhibitor and/or thepotentiator for use in this therapeutical method.

BACKGROUND OF THE INVENTION

CF is an autosomal recessive disorder, the most common lethal geneticdisease in Caucasians, (O'Sullivan 2009; Rowe, 2005; Accurso, 2006)characterized by chronic lung disease, the main cause of morbidity andmortality, pancreatic dysfunction, raised electrolyte levels in sweat,and male infertility. CF is caused by mutations of one single protein,the cystic fibrosis transmembrane conductance regulator (CFTR), acAMP-regulated chloride channel that is primarily located at the apicalmembrane of epithelial cells (Park 2010). More than 1500 differentdisease-associated mutations have been identified, some of them encodingCFTR mutants reaching the cell plasma membrane but lacking CFTRactivity, other ones encoding negligible amounts of protein or misfoldedmutants that are prematurely degraded and fail to reach a cell surfacelocalization. Among the latter, a single codon deletion, ΔF508, occursin about 90% of CF patients on at least one allele. Due to its misfold,ΔF508-CFTR loses its essential ion channel activity at the plasmamembrane (PM), thus provoking local inflammation, increasedsusceptibility to respiratory bacterial infections, and progressivepulmonary and digestive insufficiency (Collins 1992).

A still partially functional ΔF508-CFTR can be rescued at the plasmamembrane (PM) by molecules that correct ΔF508-CFTR intracellularretention and degradation (correctors). However, ΔF508-CFTR that reachesthe PM is unstable as result of a [carboxyl-terminus heat shock cognate70 (Hsc70)-interacting protein] (CHIP)-mediated ubiquitination, followedby redirection of the protein from endosomal recycling towards lysosomaldelivery and degradation (Okiyoneda T, 2010). Therefore, CF patientscarrying the misfolded ΔF508-CFTR are poorly responsive to potentiatorsof CFTR channel activity that can be used for the treatment of the smallsubset of CF patients that carry PM-resident CFTR mutants (Ramsey B W,2011; Davids P B, 2011). Therefore, fixing the misfolded ΔF508-CFTRmutant at the PM after rescue is the principal objective of“CFTR-repairing” therapies (Lucaks G L, 2012; Davids P B, 2011).

An ideal therapy for CF should aim not only at rescuing CFTR function,but also at ameliorating chronic lung inflammation and the increasedsusceptibility to bacterial infections that constitute the main clinicalproblem of CF patients (Belcher C N, 2010). A recent clinical trial withthe CFTR corrector VX-809 in ΔF508-CFTR homozygous patients demonstratedmodest dose-dependent reductions in sweat chloride (Clancy J P 2012;Elborn S. 2012). However, no improvement in lung function or CFcomplications was reported (Clancy J P 2012; Elborn S. 2012), and PhaseII clinical studies combining VX-809 and the potentiator VX-770 have tobe awaited to evaluate their clinical benefit.

We have reported that a complex derangement of protein homeostasis(proteostasis) occurs in CF epithelial cells and is caused by the lossof CFTR function. Increased levels of reactive oxygen species (ROS)induced by defective CFTR function lead to tissue transglutaminase (TG2)activation driving cross-linking and aggresome accumulation of severalTG2-substrate proteins (Maiuri L, 2008; Luciani A, 2009), among whichthe sequestration of the essential autophagy protein Beclin-1 (LucianiA, 2010; Luciani A, 2011). The functional sequestration of Beclin 1disloges the PI3K complex III away from the endoplasmic reticulum (ER),thus inhibiting autophagosome formation and driving inflammation in CFairways. This generates a feed forward loop that sustains oxidativestress and perpetrates inflammation. Defective autophagy was alsoconfirmed in CF macrophages (Abdulrahman B A, 2012). Rescuing Beclin-1and autophagy either by transfection-enforced Beclin 1 overexpression orby means of TG2 inhibitors (e.g. cystamine) or antioxidants (e.g.N-acetyl-cysteine or the superoxide dismutase (SOD)/catalase-mimeticEUK-134), blunts inflammation in ΔF508-CFTR homozygous airways, both inmice in vivo and in human tissues, in vitro (Luciani A, 2010; Luciani A,2011). Moreover, rescuing autophagy favors ΔF508-CFTR trafficking to theplasma membrane of the epithelial cells.

DESCRIPTION OF THE INVENTION

Using different in-vitro, ex vivo and in-vivo experimental models ofΔF508-CFTR cystic fibrosis, it was surprisingly found that pre-treatmentwith either a TG2-inhibitor or an agent inhibiting reactive oxygenspecies (ROS inhibitor) or a combination thereof, enables the action ofCFTR potentiators on ΔF508-CFTR well beyond withdrawal of the TG2inhibitor and/or of the ROS inhibitor, thereby enabling for the firsttime an effective and long-lasting therapeutic approach to cysticfibrosis caused by ΔF508-CFTR mutation.

It was first established an ex-vivo experimental setting where primarynasal epithelial cells freshly obtained by nasal brushing fromΔF508-CFTR homozygous patients were incubated for 18 hrs with eithercystamine or EUK-134 or with the well known CFTR correctors Corr-4a andVRT-325 (Varga K, 2008) followed by wash and re-culture for 24 hrs withmedium. At the end of incubation it was assessed CFTR channel functionby a standardized procedure of assessment of iodide efflux (Silvis M R2009). Surprisingly it was found that cystamine and EUK-134, wereeffective not only to rescue ΔF508-CFTR function, but also, unlikeCorr-4a and VRT-325, to render the cells capable of conservingΔF508-CFTR response to CFTR potentiators genistein, VX-532 well beyonddrug washout. Therefore, it is provided the unpredictable evidence thatCFTR potentiators can turn out effective on ΔF508-CFTR in human CFairway epithelial cells if the environment has been previously restoredby proteostasis regulators as cystamine or EUK-134.

It was used another human ex vivo experimental setting where nasal polypbiopsies were obtained from ΔF508-CFTR homozygous patients, as idiopaticnon-allergic nasal polyposis often complicate CF. ΔF508-CFTR homozygousnasal polyp biopsies were treated with cystamine for 18 hrs, washed andthen cultured for further 36 hrs in the absence of cystamine.Surprisingly, in this experimental model, the nearest to in vivosituation, as different cell types may interact with the neighbouringcells within their natural environment, the reduction of signs ofmucosal inflammation coupled with a conserved CFTR expression at theepithelial surface, persisted for 36 hrs after cystamine withdrawal.Moreover, in this setting, an extended experimental procedure consistingof a single short pulse of biopsies with the above mentioned CFTRpotentiators at the end of washout period, significantly increased theeffects of cystamine in damping down mucosal inflammation while CFTRpotentiators were totally uneffective on biopsies that were notpre-treated with cystamine. These results demonstrate a synergisticeffect of sequential treatment of cystamine plus genistein and providethe unexpected evidence that CFTR potentiators are beneficial inΔF508-CFTR airways provided that the ΔF508-CFTR is firstly stabilized atthe plasma membrane of airway epithelial cells by pre-treatment withcystamine.

To prove the efficacy of such a sequential drug administration onΔF508-CFTR in vivo, it was used another experimental setting where micehomozygous for the ΔF508-CFTR (Cftr^(F508del)) were administeredintraperitoneally for 7 days with vehicle alone or with the TG2inhibitor cystamine. The latter proved able in vitro and in ex vivohuman CF airway samples to prolong the expression of ΔF508-CFTR at theepithelial surface beyond drug washout. In this experimental model, theeffects of cystamine in sustaining re-location of ΔF508 protein at thelung epithelial surface and in reducing lung inflammation persisted for10 days after cystamine withdrawal. In an extended experimental settingwhere Cftr^(F508del) mice were treated with daily inhalations of eitherintraperitoneal or aerosolized cystamine for one week, kept for anotherweek without treatment and then sequentially pulsed with the potentiatorgenistein, the signs of lung inflammation, either constitutive orelicited by Lipopolisaccharide from Pseudomonas Aeruginosa (PA-LPS) weresignificantly reduced in cystamine-pretreated mice by the CFTRpotentiator that, on the contrary, was uneffective in mice that had notreceived cystamine pre-treatment.

To provide the rationale for the use of either TG2 inhibitors or drugsthat reduce ROS levels as pre-treatment before the administration ofCFTR potentiators, another experimental setting was used, where airwayepithelial cell lines carrying ΔF508/ΔF508 CFTR mutations were treatedwith cystamine or EUK-134 or where TG2 was depleted by a smallinterference RNA approach or where ROS were reduced by theoverexpression of the human Manganese Superoxide-dismutase (Mn-SOD). Ina first group of experiments, cells were pre-treated for 18 h withcystamine or EUK-134 and then kept in medium alone for further 48 h andfinally pulsed with genistein or VX-532, as above indicated. In anotherexperimental setting, TG2 gene silencing or Mn-SOD overexpression wereperformed instead of incubation with cystamine or EUK-134 and cells wereanalyzed after 48 h. The analysis of CFTR function after treatmentsrevealed that either pharmacological pre-treatments or TG2 knock down orMn-SOD overexpression were similarly effective in enabling the action ofCFTR potentiators in stimulating CFTR channel function. These resultsdemonstrate that the effects of cystamine and EUK-134 rely on theirability to inhibit TG2 activity and/or reduce ROS levels.

Another experimental approach was used to test the efficacy of otherpharmacological agents able to damp down TG2 and/or reduce the levels ofROS. These pharmacological agents were molecules able to inhibit TG2activity through different mechanisms, as previously described, (hereingenerally indicated as TG2 inhibitors) as thiol compounds which arepreferably selected from the group consisting of cystamine, cysteamine,lipoic acid, tiopronin, acetylcysteine, carboxymethylcystein,erdosteine, moguisteine, mesna and glutathione (GSH). The ROS inhibitorspreferably include phenols and polyphenols such as ellagic acid, caffeicacid, cumaric acid, gallic acid, resveratrol and carotenoids such asluthein, astaxhantin and zheaxhantin. These pharmacological agents weretested following the experimental approach of pre-treatment (18 h),washout (48 h) and single pulse with potentiators, in presence orabsence of PA-LPS stimulation after pulse with potentiators, followingthe procedure above described. Using these experimental settings, it wasfound that the cysteamine, lipoic acid, tiopronin, acetylcysteine,carboxymethylcystein, erdosteine, moguisteine, mesna and glutathione(GSH), as well as the ellagic acid, caffeic acid, cumaric acid, gallicacid, resveratrol and carotenoids such as luthein, astaxhantin andzheaxhantin are endowed with similar effects as cystamine or EUK-134 inenabling the activity of CFTR potentiators genistein or VX-532 afterwashout, as described above. It was shown that all these testedsubstances were effective in reducing the levels of ROS and/or dampingdown TG2 protein and TG2 enzyme activity. It was also found that thepre-treatment with cystamine, EUK-134 as well as with the otherpharmacological agents above mentioned, enables the activity of the CFTRpotentiators genistein and VX-532 as well as of the well known CFTRpotentiator VX-770 on ΔF508-CFTR 48 h after withdrawal of the moleculesused as pre-treatment regimen.

Moreover, the efficacy of other molecules endowed with either ROSinhibiting activity or potentiator activity was tested. It was foundthat quercetin, silybin, apigenin, catechin, epigallocatechin,antocyanidins were as effective as genistein in stimulating CFTRfunction after pre-treatment with all the above mentioned moleculesfollowed by 48 h of washout.

Altogether, these results support a novel approach for the treatment ofF508-CFTR homozygous patients. Particularly these results indicate thatthe inhibition of TG2, as well as the reduction of ROS levels whichsustain TG2 expression, induce and conserve ΔF508-CFTR protein at theepithelial surface after rescue thereby allowing potentiators to exerttheir activity of channel function enhancer on the ΔF508-CFTR stillresident at the cell surface after drug suspension.

Accordingly, the present invention provides a combination of (i) atissue transglutaminase TG2 inhibitor and/or (ii) an agent able toreduce the levels of reactive oxygen species (ROS inhibitor) and (iii) achannel activator (potentiator) of cystic fibrosis transmembraneconductance regulator (CFTR), for use in a method of treatment of acystic fibrosis patient carrying the ΔF508-CFTR mutation, whichcomprises administering to said patient, the tissue transglutaminase TG2inhibitor and/or the agent able to reduce the levels of ROS followed bythe potentiator.

The agents generally indicated as TG2 inhibitors are thiol compoundswhich are preferably selected from the group consisting of cystamine,cysteamine, lipoic acid, tiopronin, acetylcysteine,carboxymethylcystein, erdosteine, moguisteine, mesna and glutathione(GSH). The TG2 inhibitor cystamine is particularly preferred.

The ROS inhibitors preferably include phenols and polyphenols such asellagic acid, caffeic acid, cumaric acid, gallic acid, resveratrol andcarotenoids such as luthein, astaxhantin and zheaxhantin.

Molecules that can be used as potentiators according to the presentinvention are disclosed in:

-   Davison H R et al, “Fluorinated DF508-CFTR correctors and    potentiators for PET imaging, Bioorganic & Medicinal Chemistry    Letters 22 (2012) 1602-1605;-   Becq F et al, “Pharmacological therapy for cystic fibrosis: from    bench to bedside”, Journal of Cystic Fibrosis Volume 10 Suppl    2 (2011) S129-S145;-   Moran O, “Model of the cAMP activation of chloride transport by CFTR    channel and the mechanism of potentiators”, Journal of Theoretical    Biology 262 (2010) 73-79;

which are herein incorporated by reference in their entirety.

In a preferred embodiment, the potentiator is the compounds VX770 (FlumeP A et al; for the VX08-770-104 Study Group. Ivacaftor in Subjects withCystic Fibrosis who are Homozygous for the F508del-CFTR Mutation. Chest.2012 Mar. 1).

-   Ramsey B W et al, VX08-770-102 Study Group A CFTR potentiator in    patients with cystic fibrosis and the G551D mutation. N Engl J. Med.    2011 Nov. 3; 365(18):1663-72;-   Accurso F J et al, Effect of VX-770 in persons with cystic fibrosis    and the G551D-CFTR mutation. N Engl J. Med. 2010 Nov. 18;    363(21):1991-2003).

In an invention embodiment, the TG2 inhibitor and/or ROS inhibitor areadministered to the patient for a period of 1 to 4 weeks, preferably fora period of 1 to 2 weeks.

At the end of said period of time, the administration of TG2 inhibitorand/or ROS inhibitor is stopped and the administration of potentiator isstarted and protracted.

In an alternative therapeutic regimen, the administration of TG2inhibitor and/or ROS inhibitor is periodically resumed at intervals of 4to 6 weeks during the administration of the potentiator, depending onthe patient's response to the potentiator. In particular, theTG2-inhibitor and/or ROS inhibitor supply will become necessary wheneverthe effects of the potentiator therapy diminish and CF symptoms such aslung function significantly worsens or markers of inflammation,pancreatic dysfunction, or liver involvement as well as sweatelectrolyte concentrations significantly increase. In this case, theadministration of TG2 inhibitor and/or ROS inhibitor during potentiatortherapy should last as long as necessary for patient's recovery fromcystic fibrosis symptoms, generally for a period of 1 to 4 weeks.

The TG2 inhibitor, ROS inhibitor and the potentiator are preferablyadministered through the oral, respiratory or parenteral routes.Generally the pharmaceutical form and administration route will bedetermined on the basis of the specific molecule selected for therapy.

In another embodiment of invention, an agent possessing activity ofeither TG2 inhibitor or potentiator is co-administered with the TG2inhibitor, the ROS inhibitor or with the potentiator. These agents arepreferably flavonoids selected from quercetin, silybin, genistein,apigenin, catechin, epigallocatechin, antocyanidins.

The therapeutic treatment according to the present invention isconveniently administered to subjects diagnosed by genetic testingpositive for ΔF508 mutations and positive sweat test, as well as toinfants early diagnosed by newborn screening in order to early preventstructural lung damage.

The dose of TG2 inhibitor and of potentiator will be adapted to thespecific situation taking into account patient's age, general healthconditions, weight, other concomitant therapies and responsiveness tothe combined treatment over time.

Another embodiment is a pharmaceutical composition containing a TG2inhibitor and/or a ROS inhibitor and/or a potentiator as above defined,for use in a method for the treatment of ΔF508 cystic fibrosis accordingto the present invention. The composition is in a suitablepharmaceutical form for oral, aerosolized or parenteral administrationand contains an effective amount of active ingredients together withpharmaceutically acceptable excipients.

The invention is further illustrated by the following examples and theannexed Figures.

DESCRIPTION OF THE FIGURES

FIG. 1. Cystamine and EUK-134 sustain ΔF508-CFTR channel function beyonddrug washout and enable the action of the potentiators genistein orVrx-532 in freshly isolated brushed nasal epithelial cells fromΔF508-CFTR homozygous CF patients.

(A, B) Freshly isolated brushed nasal epithelial cells from 5 ΔF508-CFTRhomozygous patients were incubated for 18 h with medium or Vrx-325,Corr-4a, cystamine or EUK-134, washed and then kept with medium alonefor 24 h. Brushed nasal epithelial cells from 5 non-CF controls werecultured with medium alone (WT/WT: medium). Assessment of iodide effluxby a fluorescence assay (SPQ) upon stimulation with forskolin (Fsk) plus(A) genistein (Gen) or (B) Vrx-532. SPQ fluorescence intensity (a.u.)(top) and rate of chloride efflux (bottom) measured in at least 50 cellsper experiment. Mean±SD of 3 experiments; *P<0.01 vs ΔF508/ΔF508cultured with medium (ΔF508/ΔF508: medium); ANOVA.

FIG. 2. Prior incubation with cystamine sustains ΔF508-CFTR at theairway epithelial surface and enables the activity of genistein incontrolling either constitutive or LPS-induced signs of inflammationBeyond Cystamine Washout in Nasal Mucosa from ΔF508-CFTR homozygous CFpatients.

(A, B) Nasal polyp biopsies from ΔF508 homozygous patients cultured for18 h with medium, or cystamine, followed by 36 h of incubation withmedium alone. (A) Confocal images of CFTR. Data representative of fivepatients. Scale bar 10 μm. (B) Confocal images of in situ detection ofTG2 activity and phospho-tyrosine (anti-PY-99 Ab). Data representativeof five patients. Scale bar 10 μm. (C) Left, nasal polyp biopsies fromΔF508/ΔF508 patients (n=5) pulsed for 30 min with medium or genistein(Gen) followed by 4 h of PA-LPS challenge. Right, pulses of 30 min withgenistein (Gen) followed by 4 h of PA-LPS challenge in nasal polypbiopsies from ΔF508/ΔF508 patients (n=5) pre-treated with cystamine for18 h, then washed and kept in medium alone for 24 h. Confocal microscopyimages of phospho-tyrosine (anti-PY-99 Ab). At least 30 fields wererandomly sampled on three slides from each patient. Scale bar, 10 μm.

FIG. 3. Prior treatment with cystamine enhables the activity ofgenistein in controlling lung inflammation in Cftr^(F508del) homozygousmice beyond cystamine washout.

(A, B) Cftr^(F508del) mice were treated intraperitoneally (i.p.) for 7days with PBS or cystamine followed by 10 days of PBS (n=7 mice per eachgroup of treatment). (A) Confocal microscopy images of CFTR (cloneH182). (B) quantitative PCR analysis of TNF-α expression levels in lunghomogenates (left), ELISA detection of MIP-2 protein levels in lunghomogenates (middle) and number of CD68′ macrophages (per mm² of lungtissue) counted in 15-20 different random selected fields per lung permouse for each experimental group (right). *P<0.05, **P<0.01, ***P<0.001compared to PBS treated mice (ANOVA). (C) Cftr^(F508del) mice (n=5 miceper group of treatment) treated with aerosolized cystamine or vehiclefor 7 days followed by aerosolized PBS for 10 days and then pulsed oncewith intraperitoneal genistein (Gen) followed by aerosolized PA-LPSchallenge. TNF-α expression and CD68′ macrophages counts measured as in(B). Data represent two pooled experiments (n=5 mice per group).^(#)P<0.05, ^(##)P<0.01, vs PBS treated mice, respectively; ^(§)P<0.05;ANOVA.

EXAMPLE 1 Cystamine and Antioxidants Induce and Sustain Channel Functionof Rescued ΔF508-CFTR in Primary Brushed Nasal Epithelial Cells FromΔF508/ΔF508 Patients

We examined whether cystamine or EUK-134 (Luciani A, 2010) would induceand sustain functional ΔF508-CFTR expression in freshly isolated brushednasal epithelial cells from ΔF508/ΔF508 patients (Table 1A). We usedprimary nasal epithelial cells freshly obtained from ΔF508-CFTRhomozygous patients, to directly test the efficacy of theseautophagy-rescuing strategies on CFTR function in human airways. We useda fluorescent-based SPQ halide efflux assays (Silvis M R, 2009) to testthe response to a short pulse of forskolin (FSK) added together witheither of two different CFTR potentiators, genistein or VX-532, (VanGoor F, 2010) and analyzed at least 50 brushed nasal cells for group oftreatment in each patient. Freshly isolated brushed nasal epithelialcells were incubated for 18 h with either cystamine or EUK-134 or withthe well known CFTR correctors Corr-4a and VRT-325. SPQ halide effluxassays revealed that in contrast to Corr-4a and VRT-325, which only hadscarce effects, transient exposure (18 h, followed by wash and reculturefor 24 h with medium) to cystamine and EUK-134 rendered the cellscapable of conserving ΔF508-CFTR response to a short pulse of forskolin(FSK) added together with either of two CFTR potentiators, genistein orVX-532 (FIG. 1).

Methods

Human Samples: Brushed Nasal Epithelial Cell.

Nasal epithelial cells freshly isolated by nasal brushing from 5 CFpatients carrying ΔF508/ΔF508 CFTR mutations (see Table 1A) and 5 non-CFage- and sex-matched controls (3F, mean age 12.5 yrs) were immersed inwashing solution (PBS, DTT 2 mM, EDTA 10 mM) at 37° C. for 1 h onthermal shaker, centrifuged at 2,300×g for 20 min and washed in PBS. Theisolated cells were maintained in 1 ml MEM Earl's salt L-Glutaminemedium supplemented with 10% FBS and the appropriate amount ofpenicillin/streptomycin. ³¹Brushed nasal cells were cultured for 18 hwith medium, Vrx-325, Corr-4a (10 μM up to 50 μM) (kindly provided byCystic Fibrosis Foundation, USA), cystamine (250 μM, Sigma-Aldrich),EUK-134 (50 μg ml⁻¹, Vinci Biochem), followed by 24 h of incubation withmedium alone.

Informed consent was obtained from all subjects and the ethicalcommittee of the University of Naples Federico II approved the study (N°290/09).

TABLE 1A Clinical characteristics of Cystic Fibrosis patients Patients #1 2 3 4 5 Sex; F M F M F Age* 11, 2  13, 2  12 15 10, 1  Age atdiagnosis* 1, 2 0, 9 2, 4 0, 8 1, 6 Genotype ΔF508/ ΔF508/ ΔF508/ ΔF508/ΔF508/ ΔF508 ΔF508 ΔF508 ΔF508 ΔF508 Pancreatic Yes Yes Yes Yes Yesinsufficiency Chronic Yes No Yes Yes No respiratory infection (PA) MeanFEV1, % predicted 78 72 73 69 70 # patient's number *(years, months)

Iodide Efflux.

The iodide-sensitive fluorescent indicator, SPQ (Molecular Probes,Eugene, Oreg.) (Silvis M R, 2009) was introduced into cells in ahypotonic solution of iodide buffer (in mM: 130 NaI, 4 KNO₃, 1 Ca(NO₃)₂,1 Mg(NO₃)₂, 10 glucose and 20 HEPES, pH 7.4) diluted 1:1 with water andcontaining a final concentration of 10 μM SPQ. Cells were loaded for 20min at 37° C. in a humidified chamber with 5% CO₂. The SPQ-loaded cellswere then mounted on a LSM510 Meta confocal microscope with a 37° C.heated stage and perfused with iodide buffer. Changes in CFTR-mediatedSPQ fluorescence were monitored at the 445 nm wavelength in response toexcitation at 340 nm during perfusion at 37° C. in nitrate buffer (NaIreplaced with 130 mM NaNO₃) for 10 min with 20 μM forskolin plus 50 μMgenistein or 20 μM forskolin plus 20 μM VRX-532 (kindly provided byCystic Fibrosis Foundation, USA). The peak iodide efflux rate (usually12 min after forskolin plus genistein or forskolin plus Vrx-532) oftreated or untreated cells was calculated in accordance with theStern-Volmer relationship as follows:(F _(o) /F)−1=KC _(Q)

where F is the observed fluorescence, F_(o) is the fluorescence in theabsence of a quenching anion, C_(Q) is the concentration of thequenching anion, and K is the Stern-Volmer quench constant. The rateswere calculated using SigmaPlot Version 7.1 for each mean fluorescencetrace generated from the 50 cells examined per population per coverslip.

Statistical Analysis.

Data are reported as arithmetic mean±SD. Data distribution was analyzedfor normality and statistical analysis performed using the one-wayANOVA. Significant differences are indicated in the figures. All datawere obtained from independent measurements. Data were analyzed usingSPSS 13 software. Statistical significance was defined as P value of<0.05.

EXAMPLE 2 Cystamine Re-Establishes ΔF508-CFTR Expression in Human NasalPolyp Mucosae from CF Patients

To translate these findings to human CF airways, we used an ex-vivomodel of cultured nasal polyp biopsies belonging to CF patients, auseful tool to test potential strategies of modulation of mucosalresponse to environmental triggers within their natural environment(Raia V, 2005, Maiuri L, 2008).

Nasal polyp biopsies from five ΔF508/ΔF508 patients (Table 1B) weretreated with cystamine for 18 h, washed and then cultured for further 36h in the absence of cystamine. Confocal microscopy revealed thatcystamine-mediated rescue of CFTR at the epithelial surface persistedfor 36 h after cystamine withdrawal. Moreover, the reduction of signs ofmucosal inflammation induced by cystamine, as TG2 activitation andprotein tyrosine phosphorylation, persisted after 36 h of washout (FIG.2).

Next, ΔF508/ΔF508 nasal polyp biopsies were pulsed for 30 min withgenistein followed by 4 h incubation with PA-LPS. Genistein was noteffective in reducing epithelial protein phosphorylation. To examinewhether pre-treatment with cystamine was effective in enabling theaction of genistein in human airways, nasal polyp biopsies wereincubated with cystamine or medium for 18 h, then washed and kept inmedium alone for 24 h and finally pulsed for 30 min with genisteinfollowed by 4 h PA-LPS. In this experimental setting a synergisticeffect of sequential treatment with cystamine plus genistein wasobserved (FIG. 2).

Our results indicate that in our system genistein has no effect on itsown, but instead potentiates the activity of ΔF508-CFTR which is stillresident at the epithelial surface well beyond washout after cystaminepre-treatment.

Methods

Human Samples: Ex Vivo Cultures of Nasal Polyp Mucosal Biopsies.

Nasal polyp biopsies from 5 ΔF508 homozygous patients undergoingsurgical treatment for non-allergic nasal polyposis (see Table 1B) werecultured as previously described,^(7,19,32) for 18 h with medium,cystamine or EUK-134, followed by 36 h of incubation with medium alone,and then pulsed for 30 min with medium or genistein followed by 4 h ofPA-LPS challenge.

Informed consent was obtained from all subjects and the ethicalcommittee of the University of Naples Federico II approved the study (N°290/09).

TABLE 1B Clinical characteristics of Cystic Fibrosis patients Patients #1 2 3 4 5 Sex; F F M M M Age* 13, 5  12, 7  13, 3  11, 8  9, 7 Age atdiagnosis* 0, 5 6, 3 1, 6 0, 4 0, 6 Genotype ΔF508/ ΔF508/ ΔF508/ ΔF508/ΔF508/ ΔF508 ΔF508 ΔF508 ΔF508 ΔF508 Pancreatic Yes Yes Yes Yes Yesinsufficiency Chronic Yes No Yes Yes Yes respiratory infection (PA) MeanFEV1, % predicted 72 68 80 74 83 # patient's number *(years, months)

Immunofluorescence and Confocal Microscopy.

The procedures were performed as previously described.

Human tissue sections: five-micrometer frozen human lung tissue sectionswere fixed in acetone for 10 min. The sections were incubated for 2 h atroom temperature with the indicated antibodies (Abs). The sections wereincubated for 2 h at room temperature with the primary Abs. The primaryAbs were: CFTR 1:100 (CF3, Abcam), CFTR 1:100 (H-182, Santa CruzBiotecnology) (used on mouse tissue), phospho-Tyr 1:200 (Santa CruzBiotecnology), p62 1:300 (Sigma). These were followed by incubation withAlexa 488 or 546 secondary antibodies (Molecular Probe, Invitrogen).Data were analyzed under fluorescence examination by a LSM510 Zeissconfocal laser-scanning unit (Carl Zeiss, Germany).

In Situ Detection of TG2 Exzyme Activity.

TG2 activity in tissue samples was detected by incubating unfixedsections with biotinylated monodansylcadaverine for 1 h at 37° C. Theincorporation of labeled substrate was visualized by incubation withAlexa 546-conjugated streptavidin (1:100; Molecular Probes, Invitrogen)for 30 min.

Statistical Analysis.

Data are reported as arithmetic mean±SD. Data distribution was analyzedfor normality and statistical analysis performed using the one-wayANOVA. Significant differences are indicated in the figures. All datawere obtained from independent measurements. Data were analyzed usingSPSS 13 software. Statistical significance was defined as P value of<0.05.

EXAMPLE 3 Cystamine Re-Establishes Functional ΔF508-CFTR Expression inCftr^(F508del) Mice and Ensures Prolonged Control of Lung InflammationWell Beyond Drug Washout

Here we examined whether prior pharmacological restoration of autophagyby cystamine could abrogate the reported lack of efficacy of CFTRpotentiators in vivo on ΔF508-CFTR homozygous airways. First, to testwhether cystamine could prolong the expression of ΔF508-CFTR at the lungepithelial surface beyond drug washout, Cftr^(F508del) mice wereadministered intraperitoneally (i.p.) for 7 days with vehicle alone orcystamine, a regimen that can ameliorate lung inflammation in vivo, orwith cystamine (7 days) followed by 10 days of vehicle only. In thisexperimental model, the effects of cystamine in sustaining there-location of ΔF508 protein at the respiratory epithelial surface andin reducing lung inflammation, persisted for 10 days after cystaminewithdrawal and were abrogated by intraperitoneal treatment with 3-MAduring the phase of withdrawal. (FIG. 3)

Next, we wondered whether these prolonged effects of cystamine couldenable the beneficial action of potentiators on ΔF508-CFTR homozygousairways. To address this hypothesis, another group of 5 Cftr^(F508del)mice was treated with daily inhalations of aerosolized cystamine (0.2mg/mouse/day) for one week, a regimen that reduced lung inflammation,kept for another week without treatment, and then sequentially pulsedwith genistein and aerosolized PA-LPS, as above detailed. Genisteinfurther improved the effects of cystamine pre-treatment and hencesignificantly reduced the signs of lung inflammation, but had no effecton its own, in mice that had not been pretreated with cystamine (FIG.3). Cystamine and genistein were both not effective in wt littermates.These results indicate that prior restablishment of proteostasis andrestoration of autophagy can create the conditions in which CFTRpotentiators become capable of alleviating lung inflammation.

Methods

Mice and Treatments.

CF mice homozygous for the ΔF508-CFTR mutation (abbreviatedCftr^(F508del))^(7,29,30) in the 129/FVB outbred background (Cftrtm1EUR,F508del, FVB/129) were used.

These studies and procedures were approved by the local Ethics Committeefor Animal Welfare (IACUC N° 382) and conformed to the EuropeanCommunity regulations for animal use in research (CEE no. 86/609).Anaesthetized Cftr^(F508del) homozygous mice were treated with dailyintraperitoneal injections of cystamine (100 μl of 0.01M in PBS) or PBSfor 7 days or with cystamine (7 days) followed by 10 days of PBS alone(n=7 mice per group). Other groups of Cftr^(F508del) mice were treatedby either intraperitoneal administration or inhalation of nebulizedcystamine (0.2 mg\mouse\day) or vehicle for one week and 7 daysfollowing cystamine withdrawal were pulsed with a single intraperitonealadministration of genistein (50 mg kg-1) followed by a challenge withaerosolized PA-LPS (10 μg/20 g body weight) (n=7 mice per group).

Real-Time and Reverse-Transcription PCR Analysis.

Total RNA was extracted with the RNeasy Mini Kit (Qiagen). The mRNA wasreverse transcribed with a SuperScript™ III First Strand SynthesisSystem (Invitrogen). Quantitative RT-PCR was performed with an iCycleriQ Multicolour Real-Time PCR Detector (Bio-Rad) with iQ™ SYBR Greensupermix (Bio-Rad). Expression levels of genes were normalized to GAPDHlevels in the same sample. The relative amounts of mRNA were calculatedby using the comparative Ct method. Real-time RT-PCR analyses wereexecuted for evaluating efficiency of TNF-α. The sequence of TNFαprimers were:

Forward: CCACCACGCTCTTCTGTCTA; Reverse: AGGGTCTGGGCCATAGAACT.

ELISA.

Mouse MIP-2 secretion was measured using the BD OptEIA™ MIP-2 ELISA kitII (BD Biosciences). Values were normalized to 10⁶ cells; results areexpressed as means±SD.

Determination of Macrophage Numbers.

We prepared cryostat sections (5 μm) from lung tissues of Cftr^(F508del)mice. We fixed section on glass slides with acetone, washed withPBS-Tween (0.2%) and then incubated overnight at 4° C. with a 1:50dilution of monoclonal rat CD68 (Acris) in PBS. This was followed byincubation with Alexa-488-conjugated secondary antibodies (1:100,Molecular Probes) and DAPI (Invitrogen) nuclear counterstaining. We thenexamined them on an LSM 510 confocal microscope (Zeiss). The analysis ofmacrophage numbers was performed by Image J software and each data pointis expressed as the mean±SD of triplicate of three independentexperiments.

Immunofluorescence and Confocal Microscopy.

The procedures were performed as previously described (Luciani A, 2010).

Mice lung tissues: seven-micrometer frozen lung tissue sections fromeach mice were fixed in acetone for 10 min. The sections were incubatedfor 2 h at room temperature with the primary Abs. The primary Abs were:CFTR 1:100 (CF3, Abcam), CFTR 1:100 (H-182, Santa Cruz Biotecnology)(used on mouse tissue), phospho-Tyr 1:200 (Santa Cruz Biotecnology), p621:300 (Sigma). These were followed by incubation with Alexa 488 or 546secondary antibodies (Molecular Probe, Invitrogen). Data were analyzedunder fluorescence examination by a LSM510 Zeiss confocal laser-scanningunit (Carl Zeiss, Germany).

In Situ Detection of TG2 Exzyme Activity.

TG2 activity in tissue samples was detected by incubating unfixedsections with biotinylated monodansylcadaverine for 1 h at 37° C. Theincorporation of labeled substrate was visualized by incubation withAlexa 546-conjugated streptavidin (1:100; Molecular Probes, Invitrogen)for 30 min.

Immunoblot Analysis.

The protein of lung homogenates were obtained from treated and untreatedmice and the amounts of proteins were determined by a Bio-Rad proteinassay to ensure equal protein loading before Western blot analysis.Fifty micrograms of protein were loaded in each lane. Antibodies againstp62, 1:1000 (Sigma), and αβ-tubulin, 1:1000 (Cell Signaling Technology)were used as primary antibodies. Densitometric analysis was performedwith Image J software; each data point is expressed as a mean±SD oftriplicate of three independent experiments.

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The invention claimed is:
 1. A method of treating a cystic fibrosis inpatients carrying ΔF508-CFTR mutation and positive for cystic fibrosis,said method comprising administering to said patients a combination ofa) a tissue transglutaminase TG2 inhibitor and b) a channel activator(potentiator) of cystic fibrosis transmembrane conductance regulator(CFTR) and treating said cystic fibrosis.
 2. The method according toclaim 1, wherein the TG2 inhibitor is administered for a period of 1 to4 weeks.
 3. The method according to claim 2, wherein the TG2 inhibitoris administered for a period of 1 to 2 weeks.
 4. The method according toclaim 2, wherein at the end of said period of time the administration ofTG2 inhibitor is stopped and the administration of the potentiator isstarted.
 5. The method according to claim 4, wherein the administrationof TG2 inhibitor is resumed at intervals of 4 to 6 weeks during theadministration of the potentiator.
 6. The method according to claim 5,wherein said resumed administration of TG2 inhibitor is carried out overa period of 1 to 2 weeks.
 7. The method according to claim 1, whereinthe TG2 inhibitor and the potentiator are administered through oral,respiratory or parenteral routes.
 8. The method according to claim 1,wherein said patient is genetically diagnosed positive for ΔF508 cysticfibrosis or is positive to the sweat test.